Bearing platform and method for peeling-off type laser cutting-up wafer

Abstract

The invention discloses a bearing platform for peeling-off type laser cutting-up wafers and a method of the bearing platform, and relates to the field of wafer cutting-up, and the key points of the technical scheme are that the bearing platform comprises a bearing platform shell, a linear motion device, a micro mechanical arm device and a crystal grain collector, and the bearing platform shell is used for placing a to-be-cut-up wafer; the linear motion device is installed on the bearing platform shell, the micro mechanical arm device is installed on the linear motion device and located below a wafer to be cut, and the crystal grain collector is installed below the micro mechanical arm device. After the end effector reaches the center position of the crystal grain, vacuum adsorption is started to firmly fix the crystal grain, when the laser cutting head carries out machining and auxiliary gas blowing is carried out, the crystal grain can be kept fixed, the cutting precision when the laser head cuts and routes is improved, and it is guaranteed that the crystal grain is not blown off and damaged.

Description

Technical Field

[0001] The invention relates to the field of wafer scribing, and more particularly to a carrying platform and a method for peeling-off laser scribing wafers. Background Art

[0002] Laser wafer scribing has extremely high positioning accuracy and cutting quality in semiconductor manufacturing, and can achieve micron-level fine cutting. Moreover, due to the small slit width, laser cutting can minimize the waste of wafer materials and improve material utilization. Laser cutting has the characteristics of high speed and can achieve rapid wafer cutting, which helps to improve production efficiency and shorten production cycle. At the same time, laser cutting technology can also achieve cutting of complex shapes to meet special process requirements.

[0003] The existing practices for the peeling laser cutting method are as follows: 1. Laser half-cutting followed by splitting: Use a laser beam to perform partial cutting on the wafer surface, usually cutting to a certain proportion of the wafer thickness (such as 1 / 3 to 2 / 3) without completely penetrating the wafer. After the laser grooving is completed, the wafer is separated along the cutting path by applying external force (such as mechanical force, thermal stress, etc.). The force and speed need to be controlled during the splitting process to avoid wafer damage or excessive fragments; 2. Collecting after laser full cutting: When the laser is fully cut, in order to ensure thorough cutting, there must be no obstruction under the cutting path to prevent the high-temperature melting generated instantly during cutting from damaging the wafer. At the same time, since the auxiliary gas needs to be turned on during laser cutting, the auxiliary gas reduces the local temperature on the one hand, and takes away the sputtered slag on the other hand. When the cutting closed loop is completed, the cut core particles will be blown off due to the presence of the auxiliary gas.

[0004] However, in the existing laser peeling and scribing method, in order to blow away the residual waste and melt, and take away the heat generated during laser cutting, it is necessary to apply auxiliary gas to the cutting track. The bottom of the cutting track needs to be kept suspended, which is prone to flying flakes after being affected by the auxiliary gas pressure, and is prone to cracking after being blown off; 2. If special positioning columns are used to support the back of individual grains, due to the non-transparent nature of the wafer, accurate positioning on the back cannot be achieved, which greatly increases the difficulty of positioning. This method cannot be fixed, and there are too many limiting factors. When the auxiliary gas is turned on, there is still a great risk of being blown away.

[0005] Therefore, new solutions need to be proposed to solve this problem. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a carrier platform and method for peeling-off laser wafer dicing. By loading a micro-robotic arm suitable for the size of the grains and its corresponding encoding method, in conjunction with a grain collection device, it is possible to achieve chip dicing in a specific area within the entire wafer, and place the separated grains in designated locations, ensuring that the single chip is intact and undamaged.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions: the supporting platform for the peeling-type laser-slicing wafer includes a supporting platform shell, a linear motion device, a micro-robotic arm device, and a grain collector. The supporting platform shell is used to place the wafer to be sliced, the linear motion device is installed on the supporting platform shell, the micro-robotic arm device is installed on the linear motion device and is located below the wafer to be sliced, and the grain collector is installed below the micro-robotic arm device.

[0008] Furthermore, the micro-robotic arm device includes a robotic arm mounting platform, a telescopic cylinder is arranged on the robotic arm mounting platform, the telescopic cylinder can rotate around its own axis, a second robotic arm is arranged on the telescopic cylinder, a first robotic arm is arranged on the second robotic arm, the second robotic arm can achieve a large range of spatial posture adjustment, the first robotic arm can achieve a small range of spatial posture adjustment, the first robotic arm is arranged on the first robotic arm, the grain end effector is freely rotated about the joint mounting center of the first robotic arm and can be used to adsorb grains.

[0009] According to the above-mentioned peeling laser dicing wafer carrier platform dicing method, including the wafer position area coding method, the wafer notch is used as a reference, divided into two directions, X and Y, and the X direction is evenly divided into grid lines with equal spacing, and each grid line is recorded as X 1 , X 2 ,…,X j ,X j+1 ,…,X j+n , used to mark the position of the cutting line in the X direction. In order to facilitate the computer to read the position and perform calculations, this group of marks and Arabic numerals are matched one by one to form a letter and number coding set. The mapping relationship between the two sets is {X 1 , X 2 , …, X i , X j+1 , …, X j+n}→{1, 2, …, j, j+1, …, j+n}. Similarly, the Y direction is encoded as {Y 1 , Y 2 , …, Y i , Y i+1 , …, Y i+n}→{1, 2,…,i,i+1,…,i+n};

[0010] The cutting line position is determined, the length of a single grain is L, the width is W, and the cutting area is recorded as (X j , X j+1 , Y i , Y i+1 ), the coordinates of the center point of the grain are [(j+1 / 2)*L, (i+1 / 2)*W], and the positioning coordinates of the end effector of the grain are [(j+1 / 2)*L, (i+1 / 2)*W].

[0011] Furthermore, the intersection of the telescopic rotating cylinder axis and the robot arm installation platform is taken as the coordinate origin to establish the origin coordinate system C 0 , the axis direction is the coordinate axis z 0 ; Take the rotation axis of the second robot arm as C 1 Coordinate system, axis direction is Z 1 ; And so on to establish C 2 , C 3 Coordinate system;

[0012] In the present invention, the telescopic rotary cylinder, the second mechanical arm, the first mechanical arm, and the grain end effector are all connecting rod structures. According to the connecting rod coordinate system transformation matrix Expand to get:

[0013]

[0014] d i is the connecting rod offset, is the joint rotation angle, α is the connecting rod torsion angle, and the transformation relationship of the end relative to the origin coordinate system in the present invention is The relationship between the grain position and the origin coordinates can be determined as By adjusting the joint rotation angle and the connecting rod torsion angle α according to the position, the end effector of the grain can be accurately positioned at the center of the grain.

[0015] Furthermore, according to the size of the grain and the cutting area where it is located, the center coordinate point [(i+1 / 2)*W, (j+1 / 2)*L] can be determined, and the coordinate center point is the positioning point of the end effector of the grain;

[0016] The end effector determines the origin coordinate system C according to the positioning point information 0 and the end effector coordinate system C 3 The transformation matrix of the robot arm joints is used to determine the joint rotation angles and torsion angles α of the first and second robot arms. The micromotor controls its rotation to make the end effector of the grain reach the positioning point, and turns on the vacuum mode. Ceramic micropores are opened on the end face of the end effector of the grain to adsorb the grain.

[0017] In summary, the present invention has the following beneficial effects:

[0018] 1. Improved positioning accuracy: The peeling laser anisotropic cutting platform and its method encode the wafer position area, determine the size of the wafer encoding area according to the size of the grain to be laser cut, and calculate the center position of the grain to be cut in the X and Y directions, so that the center coordinates of any grain can be obtained within the entire wafer. The micro-manipulator device uses multiple links, and obtains the link torsion angle and rotation angle based on the multi-link joint coordinate conversion relationship, so that the end effector can accurately locate any grain position, improving positioning accuracy.

[0019] 2. Protect the crystal grain from damage during the slicing process: After the end effector reaches the center of the crystal grain, it turns on the vacuum adsorption to firmly fix the crystal grain. When the laser cutting head is processing with auxiliary gas blowing, the crystal grain can be kept fixed, which improves the cutting accuracy of the laser head during slicing and routing, and ensures that the crystal grain is not damaged by being blown off. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a carrying platform in an embodiment of the present invention;

[0021] Figure 2 Schematic diagram of the structure of a micro-manipulator device in an embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the encoding method of the present invention;

[0023] Figure 4 A schematic diagram of joint coordinates is established for the micro-mechanical arm of the present invention.

[0024] In the figure: 1. Carrying platform shell; 2. Wafer to be diced; 3. Micro-robotic arm device; 4. Linear motion device; 5. Grain collector; 31. Grain end effector; 32. First robotic arm; 33. Second robotic arm; 34. Telescopic rotating cylinder; 35. Robotic arm installation machine. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0026] Example: A carrier platform for peel-off laser-scribing wafers. Figure 1 As shown, the carrying platform includes a carrying platform housing 1, a wafer 2 to be diced is placed on the carrying platform housing 1, a linear motion device 4 is mounted on the carrying platform housing 1, and a micro-mechanical arm device 3 is mounted on the linear motion device 4 and is located below the wafer 2 to be diced. A grain collector 5 is mounted below the micro-mechanical arm device 3 and is used to collect and store grains.

[0027] See also Figure 2As shown, the micro-manipulator system 3 includes a grain end effector 31, which is mounted on a first manipulator 32. The grain end effector 31 can rotate freely around the joint installation center of the first manipulator 32, and is used to adsorb grains. The first manipulator 32 is mounted on a second manipulator 33, and can rotate freely around the joint installation center of the second manipulator 33, and is used to connect the second manipulator 33 and the grain end effector 31, so as to achieve small-range spatial posture adjustment. The second manipulator 33 is mounted on a telescopic rotary cylinder 34, and is used to connect the telescopic cylinder 34 and the first manipulator 32, so as to achieve large-range spatial posture adjustment. The telescopic cylinder 34 is mounted on a manipulator mounting platform 35, and can rotate around its own axis. The manipulator mounting platform 35 is used to support the overall micro-manipulator structure and is fixed on the linear motion device 4.

[0028] Working principle:

[0029] See also Figure 3 As shown, the peeling laser dicing wafer carrying platform and method of the present invention include a wafer position area coding method, which is based on the wafer notch and is divided into two directions, X and Y. The X direction is evenly divided into grid lines with equal spacing, and each grid line is recorded as X 1 , X 2 , …, X j , X j+1 , …, X j+n , used to mark the position of the cutting line in the X direction. In order to facilitate the computer to read the position and perform calculations, this group of marks and Arabic numerals are matched one by one to form a letter and number coding set. The mapping relationship between the two sets is {X 1 , X 2 ,…,c,X j+1 , …, X j+n}→{1, 2, ..., j, j+1, ..., j+n}, similarly, the Y direction is encoded as (Y 1 , Y 2 , …, Y i , Y i+1 , …, Y i+n}→{1, 2,…,i,i+1,…,i+n}.

[0030] The cutting line position is determined, the length of a single grain is L, the width is W, and the cutting area is recorded as (X j , X i+1 , Y i , Y i+1 ), the coordinates of the center point of the grain are [(j+1 / 2)*L, (i+1 / 2)*W], and the positioning coordinates of the grain end effector 31 are [(j+1 / 2)*L, (i+1 / 2)*W].

[0031] See also Figure 4As shown, the robot arm joint coordinate system is established. The intersection of the axis of the telescopic rotating cylinder 34 and the robot arm mounting platform 35 is used as the coordinate origin to establish the origin coordinate system C 0 , the axis direction is the coordinate axis z 0 The rotation axis of the second robot arm 34 is taken as C 1 Coordinate system, axis direction is Z 1 ; And so on to establish C 2 , C 3 Coordinate system. In the present invention, the telescopic rotary cylinder, the second mechanical arm, the first mechanical arm, and the grain end effector are all connecting rod structures. According to the connecting rod coordinate system transformation matrix Expand to get:

[0032]

[0033] d i is the connecting rod offset, is the joint rotation angle, α is the connecting rod torsion angle, and the transformation relationship of the end relative to the origin coordinate system in the present invention is The relationship between the grain position and the origin coordinates can be determined as By adjusting the joint rotation angle and the connecting rod torsion angle α according to the position, the grain end effector 31 can be accurately positioned at the center of the grain.

[0034] Execute action positioning: Place the wafer in the groove step of the carrier platform housing 1, and use the wafer notch as the direction reference to determine the direction of the wafer. Use the direction of the wafer notch as the Y direction, and the direction perpendicular to the Y direction as the X direction. In the X and Y directions, divide the scribing lines evenly and evenly according to the size of the grain to be cut. The X-direction scribing line is recorded as X. 1 , X 2 , …, X j , X j+1 , …, X j+n ; The Y-direction tangent line is recorded as Y 1 , Y 2 , …, Y i , Y i+1 , …, Y i+n The whole wafer is thus divided into multiple regions of the same size as the crystal. According to the crystal size and the cutting area where it is located, the center coordinate point [(i+1 / 2)*W, (j+1 / 2)*L] can be determined. This coordinate center point is the positioning point of the crystal end effector 31. The end effector 31 determines the origin coordinate system C according to the positioning point information. 0 and the end effector 31 coordinate system C 3The transformation matrix of the robot joints is used to determine the joint rotation angles and torsion angles α of the first robot arm 32 and the second robot arm 33. The micromotor controls the rotation of the micromotor to make the grain end effector 31 reach the positioning point, and the vacuum mode is turned on. Ceramic micropores are opened on the end face of the grain end effector 31 to adsorb the grain.

[0035] Similarly, according to the cutting area (X j , X j+1 , Y i , Y i+1 ), the laser cutting head starts working, and laser cutting is performed along the cutting line in this area. At this time, the auxiliary gas is turned on. Since the grain end effector 31 has already tightly adsorbed the grain, the grain can still be kept fixed by the auxiliary gas blowing during the laser cutting process. After the cutting is completed, the micro-manipulator device 3 removes the single grain. Similarly, according to the determined grain placement position, the micro-motor controls the joint rotation angle and torsion angle α of the first mechanical arm 32 and the second mechanical arm 33, moves the grain end effector 31 to the grain placement point, turns off the vacuum adsorption, and places the grain in the collection box below. After the action is completed, it enters the zero return waiting mode to prepare for the next action.

[0036] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A carrying platform for peeling laser scribing wafers, characterized by: It includes a carrying platform shell, a linear motion device, a micro-manipulator device, and a grain collector. The carrying platform shell is used to place the wafer to be diced, the linear motion device is installed on the carrying platform shell, the micro-manipulator device is installed on the linear motion device and is located below the wafer to be diced, and the grain collector is installed below the micro-manipulator device.

2. The peeling laser scribing wafer carrying platform according to claim 1, characterized in that: The micro-robotic arm device includes a robotic arm mounting platform, a telescopic cylinder is arranged on the robotic arm mounting platform, the telescopic cylinder can rotate around its own axis, a second robotic arm is arranged on the telescopic cylinder, a first robotic arm is arranged on the second robotic arm, the second robotic arm can achieve a large range of spatial posture adjustment, the first robotic arm can achieve a small range of spatial posture adjustment, a grain end effector is arranged on the first robotic arm, the grain end effector can rotate freely about the joint mounting center of the first robotic arm and can be used to adsorb grains.

3. The method for scribing a wafer carrier platform of peeling laser scribing according to claim 1-2, characterized in that: It includes a wafer position area coding method, which is based on the wafer notch and is divided into two directions, X and Y. The X direction is evenly divided into grid lines with equal spacing, and each grid line is recorded as X1, X2, ..., X j ,X j+1 ,…,X j+n , used to mark the position of the cutting line in the X direction. In order to facilitate the computer to read the position and perform calculations, this group of marks and Arabic numerals are matched one by one to form a letter and number coding set. The mapping relationship between the two sets is {X1, X2, ..., X i ,X j+1 ,…,X j+n }→{1,2,…,j,j+1,…,j+n}. Similarly, the Y direction is encoded as {Y1,Y2,…,Y i ,Y i+1 ,…,Y i+n }→{1, 2,…,i,i+1,…,i+n}; The cutting line position is determined, the length of a single grain is L, the width is W, and the cutting area is recorded as (X j ,X j+1 ,Y i ,Y i+1 ), the coordinates of the center point of the grain are [(j+1 / 2)*L,(i+1 / 2)*W], and the positioning coordinates of the end effector of the grain are [(j+1 / 2)*L,(i+1 / 2)*W].

4. A method according to claim 3, characterized in that: Take the intersection of the telescopic rotating cylinder axis and the robot arm installation platform as the coordinate origin, establish the origin coordinate system C0, and the axis direction is the coordinate axis z0; The rotation axis of the second robot arm is used as the C1 coordinate system, and the axis direction is Z1; and so on to establish C2, C 3. Coordinate system; In the present invention, the telescopic rotary cylinder, the second mechanical arm, the first mechanical arm, and the grain end effector are all connecting rod structures. According to the connecting rod coordinate system transformation matrix Expand to get: d i is the connecting rod offset, is the joint rotation angle, α is the connecting rod torsion angle, and the transformation relationship of the end relative to the origin coordinate system in the present invention is The relationship between the grain position and the origin coordinates can be determined as By adjusting the joint rotation angle and the connecting rod torsion angle α according to the position, the end effector of the grain can be accurately positioned at the center of the grain.

5. A method according to claim 4, characterized in that: It includes performing action positioning: the wafer is placed in the groove step of the carrier platform shell, and the wafer notch is used as the direction reference to determine the direction of the wafer. The direction of the wafer notch is used as the Y direction, and the direction perpendicular to the Y direction is used as the X direction. In the X and Y directions, the scribing lines are evenly divided according to the size of the grain to be cut. The X-direction scribing lines are recorded as X1, X2, ..., X i ,X j+1 ,…,X j+n ; The tangent lines in the Y direction are recorded as Y1, Y2, ..., Y i ,Y i+1 ,…,Y i+n . This divides the entire wafer into multiple areas of the same size as the die.

6. A method according to claim 5, characterized in that: According to the grain size and the cutting area where it is located, the center coordinate point [(i+1 / 2)*W, (j+1 / 2)*L] can be determined. This coordinate center point is the positioning point of the grain end effector. The end effector determines the transformation matrix of the origin coordinate system C0 and the end effector coordinate system C3 based on the positioning point information, and determines the joint rotation angle and torsion angle α of the first and second robotic arms by the transformation relationship of the robotic arm joints. The micromotor controls its rotation to make the end effector of the grain reach the positioning point, and turns on the vacuum mode. Ceramic micropores are opened on the end face of the end effector of the grain to adsorb the grain.

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